Meeting Required Limits
At almost 200 miles long, the Cahaba River is Alabama's longest free-flowing and most ecologically diverse stretch of river. Due, in part, to nutrient overloading, several segments of the river are now impaired. Municipal wastewater treatment plants (WWTPs) that discharge into this water body are faced with extremely low nutrient requirements to restore and protect its water quality.
For the Helena WWTP, significant improvements must be made to meet the current total phosphorus requirements of 0.20 mg/L and future level of 0.043 mg/L. Coupled with an existing consent order, the Helena WWTP was facing a dire situation.
Garver's Water Team first developed a WWTP facilities plan, which included a plant-wide evaluation of existing treatment processes that identified any shortcomings that hinder current plant performance. This plan laid the framework for phased improvements to meet both current and future permit requirements.
"In the past, the city received advice from outside parties but didn't have a plan to meet the impending permit limits," said Garver Project Manager Wes Cardwell. "We worked with plant staff and city leaders to help convey what it takes to meet both the current and future permit limits, why it's important to treat for those permit requirements, and why plant improvements are necessary."
In April, construction will begin on Phase 1 improvements, which will include rehabilitation of the existing secondary clarifiers and replacement of the existing mechanisms, new tertiary filtration equipment, new chemical storage and feed facilities, and new UV disinfection equipment.